You would have to enter a radius - a margin of error. There is no way to specifically search for a coordinate, but you can approximate it. In geocaching.com map > filters > Location you can enter a GC code and get a map centred on that location. Or in project-gc > tools > live map you can get the location of the cursor in the bottom left corner so you can hover over caches to get their approx location, depending on your zoom level.
I would not recommend it added as a search filter generally unless there was a another field for tolerance (radius). (And that is a feature I would like to see!